A range of  magnets are available with different strengths. The strength of the magnet is graded according to the frequency of the NMR signals emitted by hydrogen atoms. The stronger the magnet field, the higher this hydrogen frequency. For example, with a 500 MHz magnet (11.7 T), this means that when a chemical sample is placed in the magnet for analysis, the ¹H atoms in the sample will emit signals with a frequency very close to 500 MHz. Bruker magnets are available in the range of 200-1000 MHz.

 Superconducting magnets are  electromagnets, and as such make use of the fact that an electric current produces a magnetic field. The  magnet core consists of a large coil of current carrying wire in the shape of a solenoid. At the center of the coil a very intense static magnetic field exists. The sample to be analyzed is placed inside this magnetic field.

At very low temperatures certain materials show the remarkable property of superconductivity. A superconducting wire carries electricity without the need for any driving energy (i.e. battery or mains supply). Once a current is started in a superconducting loop it will continue forever. Bruker magnets consist of such a superconducting loop. The only maintenance required on the magnet is to ensure that the coil is kept immersed in liquid helium.

The magnet consists of several sections. The outer casing of the magnet is evacuated and inner surfaces are silvered (this is the same principle as a Thermos). Next comes a bath of nitrogen which reduces the temperature to 77.35K (-195.8°C) and finally a tank of helium in which the superconducting coil is immersed in. This tank is thermally isolated against the nitrogen bath by a second evacuated section (see picture below).